The invention relates to a debarking mechanism for the decortication or pretreatment of logs for separately performed final debarking and for the discharge of at least some of the bark removed from a log stream passing through the debarking mechanism, the debarking mechanism comprising a number of rotatable debarking shafts extending parallel to the advancing direction of the logs to be fed therethrough, which are provided with a number of teeth extending beyond the circumferential surface of the shaft and arranged to strip bark off the logs being processed, transversely to the longitudinal direction of the logs, and at the same time to convey the logs transversely relative to the said shafts, the said shafts, together with the teeth thereof, being arranged to form at least a part of a support surface, on which the logs being processed travel through the debarking mechanism, and the said debarking shafts being arranged relative to each other in such a way that the logs being processed perform a rotary motion in the debarking mechanism, in which motion the logs on the support surface formed by the debarking shafts, are forced, in their turn, by the effect of the rotary motion of the debarking shafts, into the upper position, from which they roll down into the lower position on top of the other logs in the debarking mechanism.
This type of prior known debarking mechanisms are provided with fingerplates between the uppermost debarking shaft and the side wall of the debarking mechanism—in some mechanisms also between the debarking shafts—to prevent logs from being wedged between the debarking shaft and the side wall of the debarking mechanism or between two debarking shafts, and thus to prevent the wedged log from being broken.
The bark can usually be discharged from between the debarking shaft and the fingerplate or between two debarking shafts. Bark detached from the logs in long strips causes problems by clogging the gaps between the uppermost debarking shaft and the related fingerplates, thus causing the bark to collect into big clots at these uppermost fingerplates.